At is \SelectTips{a}{b} and is the meaning of {a} and {b}?
I know that the first one changing the type of the arrow, but what is the second one? The value there can be only 10,11,12....

And if I can add one more question: at the \SelectTips{eu}{} I get very small head: enter image description here

Can I increase the size of the arrow's head?

I'm using LyX (If you answer, please try to guide my via this software)....

Thank you!

1 Answer 1


From xy:

According to the documentation of XY-pic, the declarations


will cause 12 point tips to be used. This does not appear to be the case. The only way I can seem to get larger font sizes is to add \fontscale{x}, with x taking on the values 0,h,1,2,3,4,5, after XY-pic is loaded. With 11pt you will want h and with 12pt you will want 1. The others are in case you use larger sizes for transparencies or for later reduction, in conjunction with extarticle.cls. While on the subject, I might mention that if you want thicker arrow shafts without enlarging anything else you could add the declaration

\font\xydashfont=xydash scaled \magstep1

or even larger. However, this does not thicken the arrow tips and is not really recommended. There is probably no way (short of creating your own fonts) to thicken the tips without also lengthening them.

Michael Barr - 2011

But in xypic there is only:

Finally, when XY-pic diagrams are used in conjunction with Knuth’s computer modern fonts then the declaration

\SelectTips {cm}{}

will change the tips to some that look similar, e.g.,


Kristoffer H. Rose - 2013

Please see the following issue regarding how to get bigger arrow tips: http://tug.org/mailman/htdig/xy-pic/2006-May/000366.html

  • Thank you for your answer, but I don't understand - what is the meaning of the 12? (or the other numbers that I can put there). Thank you!!
    – stud1
    Commented Dec 18, 2015 at 0:18
  • 1
    @stud1 I thought this is clear from my first quote. The number seems not to work. If you show us an MWE we can try to fix that tip or (most certainly) give a solution with tikz-cd
    – LaRiFaRi
    Commented Dec 18, 2015 at 8:37
  • Thank you! but tikz-cd doesn't work for my at lyx..... :-)
    – stud1
    Commented Dec 18, 2015 at 10:17

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